Author: UrsFormat: MarkdownItexI have given _[[interaction picture]]_ genuine content (the entry used to be effectively empty):
gave it one section "In quantum mechanics" with the standard kind of material going from interacting Hamiltonians to the definition of the [[S-matrix]], and then a section "In quantum field theory" with an outline of which steps in the previous discussion require special technical care and how.
In the process I expanded the entry _[[Dyson formula]]_. (In the end I effectively rewrote it, but now with a little broader perspective and more pointers).

gave it one section “In quantum mechanics” with the standard kind of material going from interacting Hamiltonians to the definition of the S-matrix, and then a section “In quantum field theory” with an outline of which steps in the previous discussion require special technical care and how.

In the process I expanded the entry Dyson formula. (In the end I effectively rewrote it, but now with a little broader perspective and more pointers).